The present invention relates to an earset for use in two-way voice communications which is worn in or at an ear canal of a user and which is operated hands-free. The earset of the present invention can transmit the user's voice and receive voice signals from another party simultaneously without causing feedback.
Modern wireless technologies have advanced to the extent that portable, wireless and mobile telephones have become small in size and are used widely. Such portable telephones typically include a handset requiring the use of at least one hand for communication.
A disadvantage of the handset type of telephone is that they are inconvenient to use in front of a computer or while driving a car. In such instances, the user must use a hand to hold the handset while typing at the keyboard, which is very difficult to do, or while holding the steering wheel of a car, which is dangerous. Alternatively, the user must hold the telephone handset to their ear with their shoulder, which is very uncomfortable.
In order to solve this drawback, hands-free telephones have been developed. A conventional two-way communications apparatus used with hands-free telephones comprises a headband including a speaker positioned in front of one ear and a boom attached to the headband with a small microphone at one end of the boom. With the boom connected to the headband, the microphone extends in front of the mouth of the user. However, this type of hands-free telephone is not convenient to use because it is cumbersome and because it disturbs the hair of the user.
Another conventional two-way communications system used with hands-free telephones includes a structure which hangs from the ear of the user. This type of communications system includes a speaker positioned in front of the user's ear and a boom having a microphone extending in front of the mouth of the user. Again, such a structure is not convenient for the user because it typically does not hang well at the ear and because it is bulky to carry owing to the boom.
Alternatively, as shown in FIG. 1, yet another conventional two-way communications system includes a receiver section 1 with a speaker la which is placed in the user's ear canal. Sound is transmitted to the user via an opening 1b in the back of the speaker 1a. The two way communications system also includes a transmitter section 3 which is located relatively close to the user's mouth. The transmitter section 3 includes a microphone 3a.
In the conventional two-way communications system shown in FIG. 1, however, the transmitter section 3 is attached to the receiver section 1 by a chord 2. The cord 2 also extends past the transmitter section 3 and is connected to a telephone terminal (not shown).
The two-way communications system shown in FIG. 1 does not require hands to operate. However, due to the connection of the transmitter section 3 by the cord 2, the microphone 3a dangles. With such a configuration, the microphone 3a must be omni-directional causing noise when the microphone 3a rotates at the chord 2. Additionally, with the two-way communications system shown in FIG. 1, the sound intake of the microphone 3a may be blocked by the face or clothing of the user, causing a decrease in the quality of the transmitted voice signals. Moreover, contact between the transmitter section 3 and the clothing of the user tends to cause noise.
Conventional two-way communications systems, such as those shown in FIG. 2 and FIG. 3 attempt to overcome the deficiencies described above with the two-way communications system shown in FIG. 1.
The conventional two-way communications earsets shown in FIGS. 2 and 3 integrate the speaker 1a and the microphone 3a into a single case 4. The L-shaped case 4 houses the speaker 1a in one leg and houses the microphone 3a in the other leg. In the embodiment shown in FIG. 2, the speaker 1a has a single opening 4a at a back portion thereof. Alternatively, as shown in FIG. 3, the speaker 1a may have a plurality of holes 4a'. The microphone 3a has an opening 4b through which signals are received. There is a chord 2 coming out from the lower part of the L-shaped case 4 which is connected to a telephone terminal (not shown).
By incorporating the speaker 1a and the microphone 3a in the case 4, conventional two-way communications earsets shown in FIGS. 2 and 3 solve many of the problems discussed above related to the communications system shown in FIG. 1. However, the two-way communications earsets of FIGS. 2 and 3 cause feedback because sound that leaks out from the opening 4a is fed into the microphone 3a though sound intake hole 4b. Therefore, in the communications earsets shown in FIGS. 2 and 3, either the sound volume of the speaker 1a has to be controlled below a certain level or the sensitivity of the microphone 3a has to be kept below a certain level to reduce the effects of feedback.
However, if the sound volume is maintained at a low level, the user may find it difficult to hear voice signals due to the presence of ambient noise. In an effort to reduce the effects of ambient noise, the user may cover his ear with his hand. Unfortunately, this significantly increases the acoustic coupling between the speaker and microphone, causing even more feedback.
In addition, with two-way communications earsets shown in FIGS. 2 and 3, voice signals of the user are picked up at the ear, which is about 14 cm away from the user's mouth. Conventional telephone handsets are designed to pick up voice signals directly in front of the user's mouth which are approximately 2.5 cm away from the microphone. At this distance, the level of the voice signal is approximately 94 dBSPL. Because the two-way communications earsets shown in FIGS. 2 and 3 receive voice signals further away from the mouth than conventional handsets, the signals are approximately 14 dBSPL (sound pressure level) lower than those received by a conventional telephone handset. Because the voice signals are received from further away, they require greater amplification. As a result, the systems shown in FIGS. 2 and 3 tend to pick up more ambient noise and room reverberation, both of which make the received voice signals less intelligible.
Accordingly, an object of the present invention is to provide an earset for use in two-way voice communications which is worn in or at an ear canal of the user and which is operated hands-free.
Another object of the present invention is to provide an earset which transmits the user's voice and receives voice signals from another party simultaneously without causing feedback caused by acoustic or mechanical coupling between the speaker and the microphone.
A further object of the present invention is to provide a two-way communications earset which delivers an adequate level of sound to the user without causing feedback, while also delivering an adequate level of sound to a receiver a the other end of the communication system.
A still further object of the present invention is to provide a two-way voice communications earset which is less sensitive to ambient noise at a level almost equal to a telephone handset and to room reverberation so that clear voice communications can be obtained.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.